The present invention relates to an apparatus for use in retaining bone in a desired spatial relationship. The apparatus may, for example, retain vertebrae of a spinal column in a desired spatial relationship. A known apparatus for retaining vertebrae of a spinal column in a desired spatial relationship includes a longitudinally extending member or rod which extends along the spinal column. A connector is connected with a housing of the apparatus by a pair of fasteners which engage opposite sides of the housing. A portion of a vertebra extends between the connector and the housing. An apparatus having this construction is disclosed in U.S. Pat. No. 6,656,180.